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HWIL FPGA Engineer

Allen, Texas, United States
Full Time On-site

As a HWIL FPGA Engineer, you will lead the FPGA architecture and development for Castelion's next-generation Hardware-in-the-Loop (HWIL) test capability. You will be a foundational member of a multidisciplinary team responsible for building a real-time test environment that enables rapid validation of hardware and algorithms before flight testing.

Working alongside simulation, hardware, electrical, mechanical, software, and guidance engineers, you'll develop FPGA-based solutions that bridge high-fidelity 6-DOF simulation with physical hardware, ultimately enabling fully closed-loop testing in representative mission environments.

This role is ideal for engineers who enjoy solving difficult real-time hardware challenges, working across multiple engineering disciplines, and building systems from the ground up.

Responsibilities

  • Lead FPGA architecture, development, integration, and verification for Castelion's Hardware-in-the-Loop (HWIL) test system.
  • Develop FPGA solutions supporting real-time evaluation and closed-loop hardware testing.
  • Collaborate with simulation engineers to integrate high-fidelity 6-DOF models into FPGA-based HWIL architectures.
  • Design FPGA interfaces that integrate seamlessly with radar hardware, sensors, and supporting electronics.
  • Develop high-performance FPGA implementations using high-level synthesis tools while optimizing generated RTL where appropriate.
  • Participate in system architecture definition, interface development, and hardware design reviews.
  • Develop FPGA verification strategies including simulation, timing analysis, hardware validation, and laboratory integration.
  • Support bring-up, debugging, and optimization of FPGA hardware in laboratory environments.
  • Partner closely with electrical, mechanical, software, and systems engineers to rapidly iterate HWIL capabilities using a crawl, walk, run development methodology.
  • Contribute to the evolution of the HWIL system from early open-loop demonstrations to fully closed-loop representative mission testing.

Basic Qualifications

  • Bachelor's degree in Electrical Engineering, Computer Engineering, Computer Science, or a related technical discipline.
  • 5+ years of professional FPGA development experience.
  • Experience developing FPGA solutions using VHDL, Verilog, or SystemVerilog.
  • Experience with Xilinx/AMD FPGA platforms and associated development toolchains.
  • U.S. Citizenship required.

Preferred Skills and Experience

  • Ability to generate RTL from HLS workflows while understanding and optimizing the resulting hardware implementation.
  • Strong understanding of FPGA development workflows including simulation, synthesis, implementation, timing closure, and hardware debugging.
  • Experience integrating FPGA designs with complex hardware interfaces and embedded systems.
  • Familiarity with hardware-in-the-loop (HWIL), processor-in-the-loop (PIL), or real-time simulation environments.
  • Experience supporting radar, RF, avionics, guidance, navigation, control, or aerospace systems.
  • Experience working with high-speed interfaces, real-time data processing, and deterministic hardware architectures.
  • Familiarity with laboratory integration, oscilloscopes, logic analyzers, and hardware debugging tools.
  • Ability to collaborate effectively across multidisciplinary engineering teams in a fast-paced development environment.
  • Active U.S. security clearance or the ability to obtain one is highly desired.

Other Duties

Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties or responsibilities that are required of the employee for this job. Duties, responsibilities and activities may change at any time with or without notice.

Benefits And Perks

All full-time employees are granted meaningful long-term equity, sharing in the company's significant growth trajectory. We offer four (4) weeks of paid time off, ten (10) company-paid holidays, and comprehensive health benefits - including 100% employee-covered medical and strong dependent coverage, along with dental and vision plans. We also provide paid parental leave to support growing families, a $100 monthly fitness stipend to promote health and performance, and onsite EV charging for convenience. In addition, employees enjoy perks like catered meals, company-covered food during high-demand periods, and a fully stocked kitchen to stay fueled throughout the day.

While this position does not currently require a U.S government-issued security clearance, it may in the near future. Therefore, the ability to obtain and maintain a U.S. government–issued security clearance is required. U.S. citizenship is required, as only U.S. citizens are eligible for a security clearance.

Affirmative Action/EEO Statement

About Castelion

Castelion

Castelion is one of the fastest-rising defense technology companies focused on building affordable, rapidly deployable hypersonic strike systems for the U.S. military. Founded by former SpaceX leaders, the company is working to modernize how advanced weapons are developed and manufactured—using rapid iteration, vertical integration, and scalable production to deliver next-generation deterrence capabilities faster than traditional defense programs. Castelion’s mission centers on restoring America’s ability to field advanced military technology at speed and scale.

For job seekers, Castelion offers the opportunity to work directly on some of the most advanced technologies in national defense, including propulsion systems, avionics, flight software, guidance and navigation, missile systems, and advanced manufacturing. The company hires across aerospace engineering, embedded software, manufacturing, test engineering, avionics, cybersecurity, and operations—making it especially attractive to engineers, builders, veterans, and mission-driven professionals who want hands-on ownership of real hardware.

Unlike traditional defense contractors, Castelion operates with a startup-style engineering culture modeled after rapid aerospace development environments. Employees work closely with flight hardware, testing, and production systems in a fast-paced setting where speed, accountability, and execution are prioritized. The company openly emphasizes a builder mentality—giving team members the chance to own major projects and contribute directly to systems with national security impact.

As the U.S. military increases investment in hypersonic weapons, missile modernization, and scalable deterrence capabilities, Castelion continues to grow rapidly through major government contracts and manufacturing expansion. For professionals seeking a high-growth aerospace and defense company where they can help shape the future of national security technology, Castelion is quickly becoming one of the most exciting employers in the defense innovation ecosystem.

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